As is known, a codec (coder/decoder) is used in almost all equipment that includes an audio or video component (e.g., CD players, Dictaphones, personal computers, laptops, DVD players, et cetera). In general, a codec is implemented as an integrated circuit (IC) and includes a digital interface, analog-to-digital converters, digital-to-analog converters, and analog mixing circuitry. The digital interface provides digitized signal to, and receives digitized signals from, a digital processing circuitry of the corresponding equipment. The digitized signals received via the digital interface are converted into analog signals via the digital-to-analog converters. The analog mixing circuitry may mix the converted analog signals with other analog signals or pass them unmixed to one of the outputs of the codec. Such outputs include a headphone or video driver output and a line-level output. Similarly, in an analog-to-digital converter, analog signals received are converted into digital signals wherein these signals are then digitally processed.
A codec may receive analog audio or video signals from external sources via a microphone input, line-in input, camera input, or tuner. The analog-to-digital converters convert the received analog signals into digitized signals, which are then provided to the digital interface. In addition to, or in the alternative, the received analog signals may be provided to the analog mixing circuitry for passing to an output of the codec and/or for mixing with other analog signals, where the mixed analog signals are provided to one of the audio codec outputs.
Typically, the equipment incorporating an audio or video codec includes ports or jacks operable to couple external output devices (e.g., headphones, line-out) to the analog outputs of the codec and for coupling external input devices (e.g., line-in, microphone) to the inputs of the codec. Additionally, when the output is not required, operating the codec results in decreased performance as processing capability and limited power resources are needlessly consumed.
Many manufacturers desire design flexibility when developing equipment that includes an audio or video component. Therefore, a need exists for a method and apparatus for programmable analog input/output pins of an IC.